Bainite and Superbainite in Long Products and Forged Applications*

Abstract

Abstract There is no discussion that bainite has been under the spotlight of both academic research and industrial developments in the steel industry for the past 30 years. Bainitic forging steels have long been promised to a bright future with many examples already discussed in the mid-1980s. Thirty years later, it is interesting to see whether these materials have held up to expectations and what is their current status as hot forging steel grades. Successes and difficulties are discussed over the experience at Ascometal in designing and producing bainitic steels. Further from but getting perhaps closer to industrial applications, the topic of “nanostructured” bainite or “superbainite” has attracted considerable attention over the past 15 years. Recent efforts have focused on evaluating the performances of such materials for various applications, beyond looking at basic tensile strength. This implies understanding the tensile ductility, fatigue properties and wear resistance of such materials for example, but also comparing the results to existing steel grades and other manufacturing methods, and considering the costs of the different alternatives. An overview of some recent results is provided, and collateral benefits in the investigations of these materials are also presented.